corrected example code in test_each_can_use_curly_brace_blocks_too

test_each_can_use_curly_brace_blocks_too was using the do-end block instead of the curly brace syntax for the each method.
Merge branch 'patch-1' of https://github.com/adlersantos/ruby_koans into curly

* 'patch-1' of https://github.com/adlersantos/ruby_koans:
  corrected example code in test_each_can_use_curly_brace_blocks_too